https://source.android.com/ 
/*
 * Copyright (C) 2007 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package android.widget;

import android.database.DataSetObserver;
import android.view.View;
import android.view.ViewGroup;


An adapter that links a ExpandableListView with the underlying data. The implementation of this interface will provide access to the data of the children (categorized by groups), and also instantiate Views for children and groups. 
/**
 * An adapter that links a {@link ExpandableListView} with the underlying
 * data. The implementation of this interface will provide access
 * to the data of the children (categorized by groups), and also instantiate
 * {@link View}s for children and groups.
 */
public interface ExpandableListAdapter {
    
See Also:
  • registerDataSetObserver.registerDataSetObserver(DataSetObserver)
/**
     * @see Adapter#registerDataSetObserver(DataSetObserver)
     */
    void registerDataSetObserver(DataSetObserver observer);

    
See Also:
  • unregisterDataSetObserver.unregisterDataSetObserver(DataSetObserver)
/**
     * @see Adapter#unregisterDataSetObserver(DataSetObserver)
     */
    void unregisterDataSetObserver(DataSetObserver observer);

    
Gets the number of groups.

Returns:the number of groups
/**
     * Gets the number of groups.
     * 
     * @return the number of groups
     */
    int getGroupCount();

    
Gets the number of children in a specified group.

Params:
  • groupPosition – the position of the group for which the children
           count should be returned
Returns:the children count in the specified group
/**
     * Gets the number of children in a specified group.
     * 
     * @param groupPosition the position of the group for which the children
     *            count should be returned
     * @return the children count in the specified group
     */
    int getChildrenCount(int groupPosition);

    
Gets the data associated with the given group.

Params:
  • groupPosition – the position of the group
Returns:the data child for the specified group
/**
     * Gets the data associated with the given group.
     * 
     * @param groupPosition the position of the group
     * @return the data child for the specified group
     */
    Object getGroup(int groupPosition);
    
    
Gets the data associated with the given child within the given group.

Params:
  • groupPosition – the position of the group that the child resides in
  • childPosition – the position of the child with respect to other
           children in the group
Returns:the data of the child
/**
     * Gets the data associated with the given child within the given group.
     * 
     * @param groupPosition the position of the group that the child resides in
     * @param childPosition the position of the child with respect to other
     *            children in the group
     * @return the data of the child
     */
    Object getChild(int groupPosition, int childPosition);

    
Gets the ID for the group at the given position. This group ID must be unique across groups. The combined ID (see getCombinedGroupId(long)) must be unique across ALL items (groups and all children). 
Params:
  • groupPosition – the position of the group for which the ID is wanted
Returns:the ID associated with the group
/**
     * Gets the ID for the group at the given position. This group ID must be
     * unique across groups. The combined ID (see
     * {@link #getCombinedGroupId(long)}) must be unique across ALL items
     * (groups and all children).
     * 
     * @param groupPosition the position of the group for which the ID is wanted
     * @return the ID associated with the group
     */
    long getGroupId(int groupPosition);

    
Gets the ID for the given child within the given group. This ID must be unique across all children within the group. The combined ID (see getCombinedChildId(long, long)) must be unique across ALL items (groups and all children). 
Params:
  • groupPosition – the position of the group that contains the child
  • childPosition – the position of the child within the group for which
           the ID is wanted
Returns:the ID associated with the child
/**
     * Gets the ID for the given child within the given group. This ID must be
     * unique across all children within the group. The combined ID (see
     * {@link #getCombinedChildId(long, long)}) must be unique across ALL items
     * (groups and all children).
     * 
     * @param groupPosition the position of the group that contains the child
     * @param childPosition the position of the child within the group for which
     *            the ID is wanted
     * @return the ID associated with the child
     */
    long getChildId(int groupPosition, int childPosition);

    
Indicates whether the child and group IDs are stable across changes to the
underlying data.

See Also:
Returns:whether or not the same ID always refers to the same object
/**
     * Indicates whether the child and group IDs are stable across changes to the
     * underlying data.
     * 
     * @return whether or not the same ID always refers to the same object
     * @see Adapter#hasStableIds()
     */
    boolean hasStableIds();

    
Gets a View that displays the given group. This View is only for the group--the Views for the group's children will be fetched using getChildView(int, int, boolean, View, ViewGroup). 
Params:
  • groupPosition – the position of the group for which the View is
           returned
  • isExpanded – whether the group is expanded or collapsed
  • convertView – the old view to reuse, if possible. You should check that this view is non-null and of an appropriate type before using. If it is not possible to convert this view to display the correct data, this method can create a new view. It is not guaranteed that the convertView will have been previously created by getGroupView(int, boolean, View, ViewGroup).
  • parent – the parent that this view will eventually be attached to
Returns:the View corresponding to the group at the specified position
/**
     * Gets a View that displays the given group. This View is only for the
     * group--the Views for the group's children will be fetched using
     * {@link #getChildView(int, int, boolean, View, ViewGroup)}.
     * 
     * @param groupPosition the position of the group for which the View is
     *            returned
     * @param isExpanded whether the group is expanded or collapsed
     * @param convertView the old view to reuse, if possible. You should check
     *            that this view is non-null and of an appropriate type before
     *            using. If it is not possible to convert this view to display
     *            the correct data, this method can create a new view. It is not
     *            guaranteed that the convertView will have been previously
     *            created by
     *            {@link #getGroupView(int, boolean, View, ViewGroup)}.
     * @param parent the parent that this view will eventually be attached to
     * @return the View corresponding to the group at the specified position
     */
    View getGroupView(int groupPosition, boolean isExpanded, View convertView, ViewGroup parent);

    
Gets a View that displays the data for the given child within the given
group.

Params:
  • groupPosition – the position of the group that contains the child
  • childPosition – the position of the child (for which the View is
           returned) within the group
  • isLastChild – Whether the child is the last child within the group
  • convertView – the old view to reuse, if possible. You should check that this view is non-null and of an appropriate type before using. If it is not possible to convert this view to display the correct data, this method can create a new view. It is not guaranteed that the convertView will have been previously created by getChildView(int, int, boolean, View, ViewGroup).
  • parent – the parent that this view will eventually be attached to
Returns:the View corresponding to the child at the specified position
/**
     * Gets a View that displays the data for the given child within the given
     * group.
     * 
     * @param groupPosition the position of the group that contains the child
     * @param childPosition the position of the child (for which the View is
     *            returned) within the group
     * @param isLastChild Whether the child is the last child within the group
     * @param convertView the old view to reuse, if possible. You should check
     *            that this view is non-null and of an appropriate type before
     *            using. If it is not possible to convert this view to display
     *            the correct data, this method can create a new view. It is not
     *            guaranteed that the convertView will have been previously
     *            created by
     *            {@link #getChildView(int, int, boolean, View, ViewGroup)}.
     * @param parent the parent that this view will eventually be attached to
     * @return the View corresponding to the child at the specified position
     */
    View getChildView(int groupPosition, int childPosition, boolean isLastChild,
            View convertView, ViewGroup parent);

    
Whether the child at the specified position is selectable.

Params:
  • groupPosition – the position of the group that contains the child
  • childPosition – the position of the child within the group
Returns:whether the child is selectable.
/**
     * Whether the child at the specified position is selectable.
     * 
     * @param groupPosition the position of the group that contains the child
     * @param childPosition the position of the child within the group
     * @return whether the child is selectable.
     */
    boolean isChildSelectable(int groupPosition, int childPosition);

    
See Also:
  • areAllItemsEnabled.areAllItemsEnabled()
/**
     * @see ListAdapter#areAllItemsEnabled()
     */
    boolean areAllItemsEnabled();
    
    
See Also:
  • isEmpty.isEmpty()
/**
     * @see ListAdapter#isEmpty()
     */
    boolean isEmpty();

    
Called when a group is expanded.

Params:
  • groupPosition – The group being expanded.
/**
     * Called when a group is expanded.
     * 
     * @param groupPosition The group being expanded.
     */
    void onGroupExpanded(int groupPosition);
    
    
Called when a group is collapsed.

Params:
  • groupPosition – The group being collapsed.
/**
     * Called when a group is collapsed.
     * 
     * @param groupPosition The group being collapsed.
     */
    void onGroupCollapsed(int groupPosition);
    
    
Gets an ID for a child that is unique across any item (either group or child) that is in this list. Expandable lists require each item (group or child) to have a unique ID among all children and groups in the list. This method is responsible for returning that unique ID given a child's ID and its group's ID. Furthermore, if hasStableIds() is true, the returned ID must be stable as well. 
Params:
  • groupId – The ID of the group that contains this child.
  • childId – The ID of the child.
Returns:The unique (and possibly stable) ID of the child across all
        groups and children in this list.
/**
     * Gets an ID for a child that is unique across any item (either group or
     * child) that is in this list. Expandable lists require each item (group or
     * child) to have a unique ID among all children and groups in the list.
     * This method is responsible for returning that unique ID given a child's
     * ID and its group's ID. Furthermore, if {@link #hasStableIds()} is true, the
     * returned ID must be stable as well.
     * 
     * @param groupId The ID of the group that contains this child.
     * @param childId The ID of the child.
     * @return The unique (and possibly stable) ID of the child across all
     *         groups and children in this list.
     */
    long getCombinedChildId(long groupId, long childId);

    
Gets an ID for a group that is unique across any item (either group or child) that is in this list. Expandable lists require each item (group or child) to have a unique ID among all children and groups in the list. This method is responsible for returning that unique ID given a group's ID. Furthermore, if hasStableIds() is true, the returned ID must be stable as well. 
Params:
  • groupId – The ID of the group
Returns:The unique (and possibly stable) ID of the group across all
        groups and children in this list.
/**
     * Gets an ID for a group that is unique across any item (either group or
     * child) that is in this list. Expandable lists require each item (group or
     * child) to have a unique ID among all children and groups in the list.
     * This method is responsible for returning that unique ID given a group's
     * ID. Furthermore, if {@link #hasStableIds()} is true, the returned ID must be
     * stable as well.
     * 
     * @param groupId The ID of the group
     * @return The unique (and possibly stable) ID of the group across all
     *         groups and children in this list.
     */
    long getCombinedGroupId(long groupId);
}